Energy efficiency

Considering the information in the electricity flow diagram, which change in electricity generation and delivery would most increase the efficiency (reduce the losses) of electricity delivery?

upgrading fossil fuel power plants to combined heat and power (CHP) plants

What would happen to the price of electricity in 2020 and beyond? The price of electricity would

increase

An energy efficient washing machine converts most if its electrical energy into ______ energy.

kinetic

An energy efficient light bulb converts most of the electrical energy into ______ energy.

light

By end use, what is the highest demand for electricity?

lighting

What is cogeneration?

to produce two useful forms of energy from the same fuel source.

What is the biggest expense for the average household?

heating and cooling

How much money will the smart grid save?

$2 Trillion

How much money will the smart grid cost to build?

$800 billion

Energy Efficiency = (useful energy output / total energy input) x 100 Try this problem (you will have more instruction on this later so if you don't get it correct, don't worry): While a refrigerator is working, it is using 1000 J of energy. The refrigerator is losing 200 J of energy as heat and losing 100 J of energy as sound. This means that 700 J of energy are going into keeping the food and drinks cold. How efficient is this fridge?

(200 / 1000) x 100 = 20 % efficient The heat and sound are wasted so should not be included in the useful energy: (700 / 1000) x 100 = 70 % efficient

Approximately what percentage of electricity used by schools (educational institutions) is used for lighting?

35%

How might a business generate "negawatts"? Be sure to define "negawatts"

A business could generate megawatts by turning off lights and equipment when it is not being used. They could keep lights off until it gets dark instead of automatically turning on lights, even when it's bright outdoors. Alternatively, they could use dimmer lighting when there are natural sources of bright light.

What is a green roof? How does it affect the building?

A green roof is covered with specially formulated soil and selected vegetation. Green roofs can reduce the costs of cooling and heating a building by absorbing heat from the summer sun, insulating the structure, and retaining heat in the winter.

What is a Net Zero Energy Building?

A net zero energy building produces enough renewable energy onsite to meet its energy needs over the course of a year.

How much would US oil consumption decrease by if we used all plug-in hybrid vehicles instead of traditional gasoline-powered vehicles?

According to a DOE study, replacing most of the current U.S. vehicle fleet with plug-in hybrid vehicles over three decades would cut U.S. oil consumption by 70-90%. In addition, such a move would eliminate the need for costly oil imports, save consumers money, and reduce emissions by 27%.

How has fuel efficiency changed from 1973 to 2013 (in miles per gallon)?

Between 1973 and 2013, the average fuel economy for new cars and light trucks in the United States increased from 5 kilometers per liter, or kpl (11.9 miles per gallon, or mpg), to 10.6 kpl (24.9 mpg). The government goal is for such vehicles to get 23.3 kpl (54.5 mpg) by 2025.

What could building managers do to decrease the amount of electricity used for lighting?

Building managers could decrease the amount of electricity used for lighting by turning off unnecessary lighting or having lights that automatically turn themselves on and off when there are people around. They could install more windows and skylights to let in natural light, which would reduce the amount of electric light they need. They could also install more efficient lighting that uses less electricity.

Describe how certified green buildings reduce water, CO2 emissions, energy use, and lifetime operating costs.

Certified green buildings typically reduce water use by 30-50%, CO2 emissions by 35%, energy use by 30%, and lifetime operating costs by 50-90%.

Many power plants burn fuels to produce electricity. How can energy conservation in homes and businesses lead to a reduction in emissions from power plants?

Conserving energy in your home means that less electricity has to be generated. Since most of our electricity in the United States comes from coal and natural gas, reducing the amount of electricity generation should reduce the amount of coal and natural gas being burned. If the fossil fuels are not burned, emissions will decrease.

Energy Efficiency = (useful energy output / total energy input) x 100 A heater is converting 56 J of electrical energy into 13 J of sound. There are 43 J of useful energy that is being converted from electrical energy into heat energy. How efficient is this heater?

EE = (43 / 56) x 100 = 76.8 %

Electricity demands change through the day, and across seasons. Give some reasons for increased demands during the day and across seasons.

Electricity demands change throughout the day as people are awake and using electric appliances and gadgets or asleep and using a minimum number of electric devices. Electricity demands change across seasons. In the summer, many people use more electricity because they use air conditioners to cool their living spaces. In the winter, people use more electricity for light and heating as daylights hours and shorter in the winter than they are in the summer.

An electrical grid system connects electricity producers with electricity consumers. The network allows electricity to flow where it is needed, when it is needed. What effect does energy efficiency have on the electrical grid?

Energy efficiency affects the electrical grid. When people use electricity more efficiently, electricity generators don't need to produce as much electricity. The electrical grid doesn't get overloaded. If the electrical grid is overloaded, it can overheat and go down, resulting in blackouts.

Why is the true price of gasoline higher than the price paid at the pump?

Even if a government pushes for more fuel-efficient vehicles, people do not always buy such vehicles. This is especially true when gas prices fall. Consumers do not realize that gasoline costs them much more than the price they pay at the pump.

What would happen to the fuel mix for electricity generation in 2020 and beyond?

Fewer fossil fuels would be used and More renewable fuels would be used.

How can placement of a building compared to the sun cut costs for the building (2 ways)?

Green architecture combines time-tested methods with modern materials and technology. For example, a building that is oriented to face the sun can get more of its heat from solar energy, which can cut heating costs up to 20%. This is a simple application of the solar energy factor of sustainability that people have been using for centuries.

What does green architecture focus on?

Green architecture focuses on building design that is energy efficient, resource efficient, and cost efficient. In fact, it can even help make net zero energy buildings possible.

In what ways does an refrigerator (and most other electrical devices) waste energy (select all that apply):

Heat (or thermal) energy and light energy

When using a light bulb, the electrical energy is converted into (select all that apply)

Heat or thermal energy, light or radiant energy

Explain your answers for 15-17.

I predicted that more renewable fuels and fewer fossil fuels would be used in the future. This seems to be the current path. The amount of coal used for electricity generation has decreased. I think it will continue to decrease. Natural gas will pick up some of the slack, but I think that renewable fuels will increase because of increasing efficiency and tax subsidies. If less electricity is used in the future because of conservation measures and if more of that electricity comes from renewable sources, electricity prices will rise. This is because renewable fuels are more expensive than fossil fuels.

If the batteries in these plug-in hybrids were powered by renewable sources, how much would US emission of CO2 drop by? Why is this decrease in emissions so important?

If batteries in the hybrid cars were recharged mostly by electricity produced using renewable energy (such as wind turbines, solar cells, or hydroelectric power), U.S. emissions of CO2 would drop by 80-90%. This would reduce projected climate change and save thousands of lives by reducing air pollution from motor vehicles and coal-burning power plants.

How can energy efficiency be improved?

Improving energy efficiency means using less energy to provide the same amount of work. For example, a light-emitting diode (LED) light bulb uses much less energy to produce light compared to an incandescent light bulb, which wastes 90% of its energy as heat.

Why is improving energy efficiency and reducing energy waste an important energy goal, both economically and environmentally?

Improving energy efficiency offers a variety of economic and environmental benefits. For example, it saves money and creates jobs. It results in a very high net energy, reduces oil imports, and improves energy security. It also reduces pollution and environmental degradation and helps slow climate change. Most energy analysts agree that improving energy efficiency provides the quickest, cleanest, and usually the least expensive way to achieve these economic and environmental benefits. People can cut energy waste by using mass transit and driving more energy-efficient vehicles. They can choose to buy more energy-efficient devices. They can also make simple changes to their habits. For example, people can turn off lights and electronic devices when they are not using them.

Why does improving energy efficiency increase the net energy of a given energy source?

Improving energy efficiency reduces pollution, slows climate change, and protects the environment. It also saves money, creates jobs, reduces dependence on foreign oil, and improves energy security.

Which statement is true about the efficiency of light bulbs?

Incandescent bulbs are more efficient than LED bulbs because the incandescent bulbs convert more energy to light.

In what two areas is it most important to improve energy efficiency?

Industry and Transportation

How does cogeneration improve energy efficiency?

It allows energy that would otherwise be lost to be captured for heating buildings or generating electricity.

When a house has poor insulation, there is plenty of air circulation to prevent indoor air pollution. How does a super-insulated, air-tight house prevent a build-up of air pollution?

It destroys it.

In what ways can buildings be made more sustainable over the next few decades?

Making the building industry more sustainable over the next few decades will require using energy more efficiently, using more renewable energy resources, reusing and recycling materials, and reducing pollution and waste.

Why should making more fuel-efficient vehicles be a priority?

Making vehicles more fuel efficient should be a priority in order to reduce the impacts of transportation on the environment and on human health.

What is energy efficiency?

Measure of how much useful work can be extracted from each unit of energy used.

When driving a car, what percentage of money spent on gasoline is applied to driving the car?

Most car engines are inefficient, using only about 20% of the energy from burning gasoline to keep a car moving. The other 80% is lost as waste heat. In other words, only about 20% of the money that drivers spend on gasoline actually goes toward getting them somewhere.

How can energy efficiency be improved for data centers?

Most data centers are very energy inefficient. They typically use only 10% of the electrical energy they consume. The other 90% is lost as heat. Most also run 24 hours a day at their maximum capacities, regardless of demand. They require large amounts of energy for cooling to keep servers from overheating.

Explain your answer to #2.

Most of the energy losses of electricity generation come from conversion losses. The diagram shows that the generating sources have 40.11 quadrillion Btus of energy. Conversion losses total 26.03 quadrillion Btus. This is a huge loss compared to the 1.01 quadrillion Btus lost during transmission and delivery of electricity. Reducing the number of fossil fuel plants and increasing the number of nuclear power plants will not do much to increase efficiency, as there are large energy losses from both fossil fuels and nuclear power plants. The biggest efficiency gain is to reduce the losses of the lossiest step of electricity generation.

Why does no energy-using device operate at 100% efficiency?

No energy-using device operates at 100% efficiency; some energy is always lost as heat, as required by the second law of thermodynamics.

Which industries use the most energy?

One way utility companies and industries can save energy is to use cogeneration to produce two useful forms of energy from the same fuel source. For example, the steam used for generating electricity in a power or industrial plant can be captured and used again to heat the plant or other nearby buildings instead of being released into the environment. The energy efficiency of these systems is 60-80%, compared to 25-35% for coal-powered and nuclear plants. Denmark uses cogeneration to produce 53% of its electricity, which is more than any other country. In comparison, the United States uses cogeneration to produce only 12% of its electricity.

You are going to buy a refrigerator, and you find two that have all the same features, are the same price, and are the same color and style. Option A has an energy star rating of 2 while Option B has an energy rating of 4. Which would you buy? Why?

Option B - a higher energy star rating means that the device is more efficient so less energy is being wasted. Option B - a higher energy star rating means that the device is more efficient so more energy is being wasted

What improvements could be made to your school to make it more energy-efficient?

Student answers will vary. Students may suggest more insulation, more efficient use of electricity, using less electricity, or changing the thermostat settings.

If a house has superinsulation and no air leaks, what will keep the house warm?

Superinsulation is another important feature in energy-efficient building design. Heating costs can be cut by as much as 75% when a building is well insulated and does not experience any air leaks. Heat generated from direct sunlight, running appliances, and human bodies can warm a superinsulated house with little or no need for a backup heating system, even in extremely cold climates.

What is the true cost of gasoline after the hidden costs are factored?

The International Center for Technology Assessment estimates the hidden costs of gasoline for U.S. consumers amount to $3.18 per liter ($12.00 per gallon). If people were more aware of these costs, they might be more motivated to purchase fuel-efficient vehicles.

Describe how the electrical grid works. Please include information you learned in this section and in the previous section on electricity.

The U.S. electrical grid was designed more than 100 years ago when electricity demands were much lower. Today's huge demand for electricity is stretching this outdated grid to capacity. Little investment has been made in building more transmission lines. As former U.S. Secretary of Energy Bill Richardson observed, "We're a major superpower with a third-world electrical grid system."

What is included in the industrial sector?

The industrial sector includes all facilities and equipment used to produce, process, or assemble goods. Industry accounts for 30% of the world's energy consumption and 33% of U.S. energy consumption. Industries that use the most energy are those that produce petroleum, chemicals, paper and wood products, steel, and aluminum.

What two things would allow an increase in battery-powered vehicles?

The key to greatly increasing the use of alternative motor vehicles is to ramp up research and development of suitable batteries. The ideal battery would be affordable, small, lightweight, easily rechargeable, and able to store enough energy for long-distance trips. Building a network of recharging stations within and between communities will also increase use of battery-powered vehicles.

How will a smart grid increase energy efficiency?

The smart grid will be more energy efficient, and it will help save consumers money. A smart grid will allow two-way communication between consumers and utility providers to increase energy efficiency. Smart meters will help people track how much electricity they use, when they use it, and what its cost is, essentially in real time. They can use this information to limit electricity use during times when rates are higher. According to the DOE, building such a grid will cost up to $800 billion over the next 20 years. However, it will save the U.S. economy $2 trillion during that period.

Why don't the average consumers drive hybrid vehicles?

The problem for the average consumer is that hybrid, plug-in hybrid, and all-electric cars are expensive due to the high cost of their batteries, which must be replaced every few years.

Why do people not always use more fuel-efficient vehicles?

They argue that by 2040, all new cars and light trucks sold in the United States could get more than 43 kpl (100 mpg) using available technology. Even if a government pushes for more fuel-efficient vehicles, people do not always buy such vehicles. This is especially true when gas prices fall. Consumers do not realize that gasoline costs them much more than the price they pay at the pump.

Describe how a "smart" grid will work.

This new grid will be a digitally controlled, ultra-high-voltage, high-capacity system with superefficient transmission lines.

What could you do to reduce that expense?

You could reduce heating and cooling expenses by keeping the temperature lower in the winter and warmer in the summer so that the temperature difference between inside and outside is closer together. You could also insulate your house better so that it doesn't lose heat to or gain heat from the outside as easily.

What three ways could governments encourage higher energy efficiency in transportation?

a. - Higher gasoline taxes b. - give consumers tax breaks or other economic incentives to encourage them to buy more fuel-efficient vehicles. c. - Seal your duct work

What 7 things can be done to increase energy efficiency?

a. - Make It a Team Effort. b. - Monitor Your Energy Use c. - Switch Your Bulbs. d. - Insulate Your Building. e. - Opt for Renewable Energy. f. - Stop Wasting Heat With Thermostats g. - Look for Energy Star Certified Equipment.

What are examples of ways to improve energy efficiency?

a. - Replacing incandescent bulbs with LED lighting. b. - Businesses can adjust thermostat temperatures c. - Limit air conditioner use d. - Install smart meters to monitor energy use e. - Workers can shut off computers f. - Workers can shut off printers g. - Workers can shut off nonessential lights at the end of the day h. - Workers can shut off TV's

Green architecture makes use of various techniques including

a. Building orientation & window placement to the sun b. Living/green roofs c. Superinsulation d. - Solar hot water heaters e. -electricity from solar cells f. - windows that darken automatically to deflect heat from the sun

1. Describe each type of alternative fuel technology: a. Gasoline-electric hybrid car b. Plug-in hybrid car

a. Gasoline-electric Hybrid cars have a small, traditional gasoline-powered engine and a battery-powered electric motor that provides the energy needed for acceleration and hill climbing. The most efficient current models of these cars get a combined city/highway mileage of up to 23 kpl (55 mpg) and emit about 65% less per kilometer than do comparable conventional cars. b. These cars can travel 48-97 kilometers (30-60 miles) on electricity alone. Then the small gasoline motor kicks in, recharges the battery, and extends the driving range to 600 kilometers (370 miles) or more. The battery can be plugged into a conventional 110-volt outlet and be fully charged in six to eight hours, or even faster using a 220-volt outlet. Yet another option is an all-electric vehicle that runs on a battery only.

Besides hybrid vehicles, what other ways could we cut down on energy used for transportation (3 things).

building or expanding mass transit systems, Building bike lanes along highways and city streets, Moving freight by rail instead of in heavy trucks

What would electricity consumption be in 2020 and beyond? Electricity consumption would

decrease

Energy rating of appliances is linked to how much

useful energy is produced, energy is produced, how expensive the appliance is.